You might be surprised to learn that sour cream has its roots in Mongol culinary culture. The Mongols were a largely lactose-intolerant population, but they didn’t want to cut off a potential portion of their food supply (horse milk), so they found a way to use it by creating kumis, a drink made from horse milk. The double-fermentation process made it slightly alcoholic and suitable for their lactose-intolerant population. The kumis was also less likely to spoil during long journeys in hot climates. (Notably, they also made curdled milk for the same reasons.) As the Mongols spread across Asia, they brought their kumis with them. Russians in particular took a liking to kumis, but repeated the process with their local livestock (cows) instead of horses. And instead of turning the milk alcoholic with a second fermentation, they allowed it to thicken for longer, and the slightly sour, creamy result caught on. Sour cream spread across Europe and beyond its borders, becoming especially popular in America. Today’s sour cream (along with creme fraiche and buttermilk) has its roots in Mongol and Russian fermentation practices and has become very popular in many parts of the world.